Rotary internal-combustion engine



M. L. ZIMMER ROTARY INTERNAL COMBUSTION ENGINE Nov. 15, 192

Inventor' l 7 V. Z JW/11er."

Nov. l5, 1927.

M. L. ZIMMER ROTARY INTERNAL COMBUSTION ENGINE Filed Aug. 2, 1922 m4Sheets-Sheet 2 |||l|||llrn....

Nov. l5, 1927.

M. L'. ZIMMER ROTARY INTERNAL COMBUSTION ENGINE llsss 4 Sheets-Sheet 3Filed Aug. 2. 1922 4 Sheets-Sheet 4 M L ZIMMER ROTARY INTERNALCOMBUSTION ENGIE Nov. 15, 1927.

@maia Nov. 1s, 1927.

UNITED STATES 1,649,091 PATENT OFFICE.

MEADE LAEAYETTEZIMMEE, or coEnoBA, ARGENTINA.

ROTARY INTERNAL-COMBUSTION ENGINE.

Application vfiled August 2, 1922. Serial No. 579,246.

This invention relates to an internal combustion engine of the rotarytype.

vThe/principal objects of the invention are to provide a construction ofvery simple character which will be very light per unit horse power andcan be made at small cost by anynechanicwithout any especially designedmachines or tools; to provide such' a machine of such simpleconstruction, lightness, efficiency and cheapness as to render itespecially valuable for manufacture and in small. quantities and yet ofsuch a nature that when manufactured in 4large quantities it can be putout on a very small cost basis. More specifically, the inventioninvolves a construction comprising a cylindrical casing serving as a flywheel adapted to rotate about a stationary shaft which carries elementsfor cooperating with the features of the casing to provide a pair ofexplosion chambers adapted to receive a compressed charge, explode it,and exhaust vit; and also to provide within the casing a compressionelement and to rotate the latter at the same speed as the casing but inthe opposite direction so that it can be made substantially like theexplosion chambers but will operate twice as fast so as to provide forcompressing the charges for them alternately and thus reduce the sizeofthe engine relative to the horse power generated.

An important feature of the invention consists of an expansion ringadapted to be forced aroundv on the spiral which constitutes theinternal element of the explosion and compression chambers. This takesup'the contraction between the casing and the eccentric and is adapted"to prevent the passage of gas so as to constitute a substitute for theordinary piston rings. With this I provide a substantially perfectly gastight cylinder and Ai-t permits of such a loose adjustment of theexpansion ring that the motor will turn with ease.

Additional objects and advantages of the invention will appearhereinafter.

Reference is to be had to the accompanying drawings, in whichV Fig. 1 isa side view, partly 1n central section, of a preferred embodiment ofthis 1nvention.; Y

Fig. 2 is an end view; D

Fig. 3 is an end view with the end .piece removed showing the shaft insectlon on the line 3--3 of Fig. 1;

. chamber.

Fig. 4 is a similar' viewon the line 4--4 of Fig. 1;

Fig. 5 is an enlarg d edge view of the expaison ring and t e parts forclosing its en s;

6 is a side vi'ew of the same;

Fig. 7 is a sectional view on the line 7-7 of Flg. 1, showing thegearing for rotating the compression element;

Fig. 8 is a sectional view of the same on the line 8.-"8 of'Fig. 74'

Fig. 9 is a sectional view on the line 9-9 of Fig. 2, showing theconstruction for in-`.

troducing the fuel and air;

Fig. 10 is a sectional view on the line 10`1O of Fig. 9, showing theport through which the fuel and air pass into the cylinder; Fig. 11 isan edge View of the device through which the gas enters the end of thecylinder;

Fig.l 12 is an end view of the same;

Fig. 13 is a side view of a sliding valve i ted lines the positions ofthe piston of the other explosion chamber, and

Fig. 22 is a diagrammatic longitudinal central sectional view ofthecasing and ends with the interior parts removed.

I have shown the invention in a form in which a base 10 is employedhaving end standards 11 for supporting the whole device. Through t'hesestandards extend two non-circular passages in alignment in which iscarried a shaft 12 which extends the whole length of the device and hasits ends broached off to fit the passage and hold it firmly instationary position. This shaft is provided with a ball bearing 13 ateach end having the usual cones and adjusting devices. On these bearingsare supported two end pieces '14 and 15. These end pieces are 'securedto two cylinders'l which are just alike in all respects and whichprovide the two explosion chambers. Between them is fixe-d a thirdcylinder 17 which contains the compression These three cylinders 16, 16and los . be transmitted from them in any of the ordinary ways.

It will be noted that the shaft 12 is shown at one end as provided withpassages intended to be connected with oil reservoirs, and the endpieces 14 are provided `with chambers 2O communicating with them throughtheir radial ends and with `a passa e 18 it is connected with i fuelprovided take pa through which the oil is pum' d into t e oil chamberand ball bearing or lubricating pur oses.

T e end of the shaft in addition to the oil passage 18 is provided withan air passage 19 to admit air to the oil chamber and also with a tube 8through which the oil is siphoned out of the oil chamber when the motoris at rest. The air is ventedfro'm the oil' chamber through the passage19 to permit the oil to be pumped in. As soon as the' motor stops thechamber 20 is emptied by oil sinnonmg out promptly through the tube 8.fhis tube is not absolutely necessary for the functioning of the enginebut is highly desirable for various reasons. If the oil were allowed toremain in the chamber ywith lrhe motor at rest there would be a tendencyfor the oil to leak into the combustion chamber and be forced out andwasted at the first turn of thek motor on starting. The starting of themotor would be made a good deal harder especially in cold weather. Thecirculation of the oil while the motor is runmng also serves to cool theinterior of the motor on account of the cool oil being continuallypumped into' the chamber and the heated oil wforced out through the tube8. Moreover, as the oil is not allowed to stand in the chamber no oilsediment collects in it but it colletts in the oil reservoir outsidefrom which it is easily removed.

One of the erds 14, 15 also is provided with an annular groove 22 whichis designed to' be connected with a source of explosive through acarburetor 29. This constitutes the intake for the explosive mixture.Air isadmitted with it around this groove 22. This intake is providedwith a rmg 23 in the ve 22 carrying sucti n vanes and runmng Eastfthenozzle of t e carburetor to spray e gasoline into the in- .24.Thislsapassageinthe castmg whlch constitutes the end piece and a passage25 exten through the wall of the cylinder 16. In the wall of the centralcylinder 17 is a fuel pas- 26 registering with the passa 25. p 26 has aport 27 for condibting 32 for' ends are dat and continuous. Thecylinders l 16 are substantially like them and' the two pairs ofregistering recesses 31 are filled with lead to form a counterpoise. Theinner edges of 'all these ends in both kinds of cylinders are circularand concentric with the shaft. Inside these edges fit the ends ofexpansion rings 33 in al1 these cylinders. The inner surface of eachexpansion ringris slit radially at short intervals to facilitate itsflexing and the inner surface is curved in the form of a plane spiralwhile its outer surface is cylindrical.

, As stated above, the shaft 12 is stationary. Fixed on thisshaft ineach of the two explosionI cylinders 16 is ahub. Each of these centralhubs is keyed to the Ystationary shaft 12 and has integral armsprojecting therefrom' and a rim 40 arond them forming a spider 40 havinga spiral outer surface on which fits the expansion ring, 33 havin a4similar shape inside. As the rim of t is spider is of specialsignificance I refer to it sometimes as the rim 40. This central hub hastwo pairs of passages therethrough par- I alle] witheach other fortwopairs of springs 41. These sprin are mounted on rods '42 and at the lendt ese rods pass into a yoke 43 which is guided by the side of thepassages in the hub. 'The sp bear on the inner surface ofthe rim and t eyoke 43 and tend to force the yoke outwar in a radial direction at alltimes'. On t e yoke 43 is' mounted a blade or piston 44. I have shown itas having a recessed end at 45 but the edges of this end constitutebearing surfaces. These surfaces bear against the interior surface ofthe cylinder 16, which is of cam formationyand 1n the general shape of aheart cam' 46. The rotation of the c linder about the stationary shaftcauses t is piston to move in and out radially on account-of the shapeof the cam surface 46.

iwi

The springs 41 keep the end of the piston in contact with 'the camsurfaces at all times. The piston 44 is also provided with expansionplates 44: for maintaining a gastight joint between the sides of thepiston and the walls of the cylinder.

Mounted on the spiral outer surface of this rim 40 is the xral expansionring 33 above described. 'is is not a com lete ding vring but it isprovided with a longitu inal projection 52 at each Iof its ends adaptedto almost abut| together and having e, narrow longitudinal space for aseries of cloaing plates 53, 54.and 55, there being two of Y located ateach end ol the ,cylinder iittingl in openings 59, one in each of theplates 53 Yno lill

the latten-one at each end. These plates are arranged to ht each otherso as to keep the spiral expansion ring tight around the radiallyreciprocating piston or blade at all times. The lates 53 and 54 areprovided with projections 56 at'their opposite ends sliding in notchesin the projections 52 in the ends ot Vthe expansion ring and they areprovided with overlapping ends 57 which move on each other. The plates55-are tor the purpose or closing the joint between these plates 57.A7V-shaped spring 58 is and 5l to normally hold them vin proper positiontight against the projections 52. 'llhese springsA project inwardl andare supported inside the hub and t ey are set so that the legs tend todraw the plates 53 and 54 toward each other. 4

This expansion ring, as stated, is mount- .ejd on the rim which islocated on the rim'.

d@ in the cylinder. lt is provided with a spring 60 tending to push thespiral expan-l sion ring around the spiral hub to keep it tight. ltaccomplishes this by acting on a lever 61 pivoted at 62 on' the hub andentering through an opening 63 in a notch in` the expansion ring tooperate it. The explosion and compressing cylinders are lormedsubstantially alike except that the rims d6 in the explosion cylindersare keyed to the tixed shalt 12 while the rim 40 in the centralcompression cylinder rotates thereon.

The compression cylinder is connected with the two explosion cylindersthrough" two ports'Bl opposite to each other as shown in Fig. 22. Eachot these ports is closed 'by a valve 35 located in the recess 32,pivoted on a stud at 36, and having a pin 37 which piyotally connects itwith an operating slide 38. These operating slides are moved back andlor-th to open and close the ports 34' as shown in Fig. 13 by a pair ofcams 39. 'These valves control thepassage of the compressed explosivemixture from the compression chamber into the explosion chambersalternately` and each one is opened once during each 'rotation of thecylinder. The two explosion cylinders are located with their cams 16 inopposite positions cir-l cumlerentially, the right hand `one in Fig. 1registering with the cam in the compression cylinder. v

Un the inner circumference of one, f or prelierably both, of theexplosion cylinders there is an internal gear 67 meshing with a smallergear 68 inside Vrotatable on a sta--y tionary shaft 69. fixed on the endof the explosion cylinder and having on it a pinion' 76 meshing with aigear 71v fixed to the end wall ot the compression cylinder. This isVduplicated on the other end. The gear ra.- tios of the two pairs ofgears are the same.

so that the internal gear wheel 67, rotating y ings.

Vconstantly in theforward direction, will ,turn the gear 68 with it andalso the gear 70,

compression chamber as stated above.' The compression' chambercompresses a charge and gets it ready to deliver to an explosion andexpansion chamber twice during each rotation so that each explosionlchamber providesanexplosion once during each rotation and theseexplosions occur 180"` apart. Thus, the eil'ect of the machine is adouble explosion per revolution ot the casing.

The oper tion V1will be understood more :tully by reference to the lastsheet of draw- Fig. 22 shows the course of the explosive mixture intothe compression chamber. ln the position shown in Fig. 18 t-hel mixturehas been drawn into the compression chamber by its rotation and it islilled. Now, as the casing continues to rotatevl in one direction andthe piston in the other, the parts come to the position shown in Fig. 19in which the mixture previously drawn in is being compressed at the topof the ligure while a fresh mixture is being drawn in at the bottom. Nowthe valve 35 on one side opens and the compressed charge is let into oneofthev explosion chambers. shows the next position, 180 trom Fig. 18, inwhich' the first mixture has all been compressed and `force'dout into'one of the explosion chambers as shown in Fig. 14 throu h the port 34and a new charge has been gully introduced intol the compression chamberready for compression. Fig. 21 shows the last position which, in etlect,is the same as in Figli) although the parts are in theh oppositeposition and the other valve 35 opens and lets the second compressedcharge into the other explosion chamber through the port 34 onthat side.Figs. 18 and 2 0 have the same relation to eachother also. At thisinstant the other cxplosionchamber is in the position shown in Fig. 17but the piston 44 thereof is inthe vopposite position 180 away where itis per-1 'explosion chambers, ol course, are not rotat-L ing, as stated,but the chambers themselves are'rotating with the casing of thecompression chamber. Figs. 14 and 18 show one position of the parts, Themixture, as stated, has been drawn into the compression chamber but isnot yet being discharged into the opposite explosion chamber. As theparts move from the position shown in Fig. 18 to that shown in Fig. 19,the explosion cylinder moves from-the position shown in Fig. 14 to thatshown in Fig. 15 one quart-3 ter of a revolution and the compressedmixture shown in Fig. 19 is readyto be forcedV Fig. 20- '7 i v f i intothe 'opposite cylinder through the port 34, the valve openingautomatically as stated. The explosion of the compressed mixture shownin Fig. 14 takes place at the 'oove 73 rovided to ensure a little spaceor the-exp osive mixture where the spark is caused in the usual way.Fig. 15 lshows the expansion andthe fact that the'cylinder is forcedaround from the stationar iston by the expahs'ion. The 4-same 'cylm erghen comes to the ition shown in Fig. 1 in which one hal a revolutionhas begli accomplished and the power of the explosion is aboutexhausted.- The compression chamber is now in the /position shown inFig. 20, having fully chargedthe opposite cy inder which is then inthesame position relative to they piston as shown inA Fig. 14 and readyto be 'e loded. It will be noted that the piston o the opposite cylinderbeing .180l from that shown in Fig'. .14 points m the opposite directionfrom the shaft. In Fig. 1 the exhaust takes place `through ports 74 andthe, parts are then ready to receivea neg;7 charge in the position shdwnin Fig. 14. It will be noted that the two pistons 44 in A the twoexplosion chambers are located always exactlyin thesame position becausestationary. They are shown also as extending in the opposite directionfrom the shaft,

- being 180 a art. The two explosion chambers are fixe `together so astobe in opposite positins relative to the pistons.

The ignition system can be the same as for other vm'otors and is notshown except for binding osts 72. No-timer has been shown in therawings, but this also would be attached to the end piece opposite tothat;

- whichcontains the intakeLand would of one of the ordinary kinds.

From this description, it will be seen that considerable space is savedbyrotating the and expansion and lrevents escape of the fuel at alltimes. e force exerted by the expansion of the exploded charge againstthe stationary piston or bladelocated in a radial .position is appliedat right angles to 'the radius nearly throughout the whole 3.60 degreesof the circumference. The motor 1s very sim le in construction andextremely light per orse power. Almost any mechanic can make it withoutspecially desi ed machines or tools and at small cost. lgs carburetor inthe ordinary sense has to be employed as the intake ring. takes up thefuel and s rays it into the intake.

Alt oughfI have illustrated and described only a single form of thisinvention, I am aware of the fact that modifications can be made thereinby any person skilled in the art `without departing'fromA the scope ofthe invention as expressed in the claims. Therefore, I do not wish to belimited to all the details of constructionf'herein shown and described,but what I do claim is 1. In a rotary internal combustion engine, thecombination of two explosion cylinders .and one compression cylinderrotatable in the same direction, and means for compressing the explosivemixture twice in the compression cylinder toevery ex losion in each oftheexplosion`cylinders, w ereby, char es of the explosive mixture can beintroduce from the compression cylinder'into the two explosioncyllnders, alternately, during a single revolution, and two explosionscan be obtained. 2. In a rotary internal combustion engine, thecombination of two explosion cylinders and one compression cylinderfixedly connected together and rotatable about an axis, a piston in eachcylinder, and means for ,rotating the piston in the compression cylin--der in the opposite direction to the rotation n compression chambereiectivelyrat twice the J,of the cylinder itself.

speed of the explosion hambers sofas to use .one compressionham er to-supply two exlosion chambers. .Also an increase in power 1s secured bythis means for two explosions are provided for at each revolution.ordinay inlet andl nozzle valves are entirely avolde the only valvesbeing used Vare those All 3. In a rotaryinternal combustion engine, thecombination of two explosion cylinders and one compression vchamber,iixedly connected together and rotatable about a comlmon central axis, apiston in each cylinder, means for rotating thel piston in the'compression cylinder in the opposite direction between the compressionand the .explosion to the rotation of the cylinder itself and atchamberswhich work very simply and which the same speed, and means for holdingthe `at the points -where the side pieces revolve von the expansion ringbut these surfaces are the combination of afshaft, one compression will4not give" veryfnuch-trouble on account pistons in the explosioncylinders stationary' of wear. Most of the bearing surfacesare during1'the entire rotation. y

4. In a rotary internal combustion engine,I

so narrow'that they do not create much fricahd two explosion cylindersfifed" together tion and they can be lubricated by means and rotatabletogether about said ,shaft,

' o an oil groove. f

' l meansfor conducting an explosive nixtu'r The cylinder canbemaintained gas tight/into the compression cylinder, a piston in withcomparatively loose adjustment of the the compressioncylinder, means forrotating.

expnsllon ring-so that the imotor will run said 'piston 1n the oppositedirection to' the .wit t e 0 i atest freedom. This' ,expansion rotationof the cylinder and at the K same p rmg ls'an important feature of theinvention speed, a piston in each explosion cylinder, all

i as it'automatically provides forcontraction of saidl cylinders 'havingan internal cam d means td the combination of a stationary shaft, one

it ton in the compression cylinder compression cylinder and twoexplosion cyl- 'inder and 180 apart, one

inders fixed together and rotatable'about said shaitt, means forconducting an explosion mixture into the compression cylinder apislocated radially, means for rotating the piston in a directionopposite to thatin which the cylinderfrotates, and at the same speed,statione ary pistons in the explosion cylinders, all

do of said cylinders having an internal cam ttt titi

dil

i: lll

Il ing for compressing two charges during each formation about theshaft. the casingrbeing 13' iormationior cooperatingwith theirrespective pistons, and means for conducting the compressed chargesalternately into the two explosionv cylinders. r

d. ln a rotary internal combustion engine, the combination of astationary shaft, one compression cylinder and two explosion cylindersiixed together' and rotatable about said shaft, means tor conductingexplosive mixtures into the compression cylinder, means in saidcompression cylinder .for compressing the mixture during one half of `arevolution, ports for conducting the explosive mixture irom thecompression cyl- -nder into each of the explosion cylinders,

valves for closing said ports, means tenutomatically operate saidvalves, means' in each explosion cylinder for receivin the impact of;the explosion and transmitting it to the cylinders to rotate them, saidmeans in' the two explosion cylinders being located oppositely withrespect to each other, whereby each one will provide an explosion duringone revolution of the cylinder, said explosions being 180 apart.

7. ln a rotary internal combustion engine, the combination oi rotarycasing, two ex-f plosion cylinders and one compression cylinderl in saidcasing rotatable in the saine direction, means for introducing anexplosive mixture into the compression cylinder, means in said cylinderfor compressing two charges during each revolution of the casing, meanstor introducing one of said `charges into one ot the explosion cylindersand the other into the other, and means in said lexplosion cylinders forigniting the two charges therein once during each revolution.

8. ln a rotary internal combustion engine,l the combinationi a rotarycasing, two explosion cylindeitv and one compression cylinder in saidcasing rotatable together, means for introducing an explosive mixtureinto the compression cylinder, means in said casrevolution of thecasing,'means for in troducmg one of said compressed charges 1nto one ofthe explosion cylinders', and other into A the other,.means in saidexplosive cylinders for igniting the charges alternately once duringeach revolution, two valves for controlling the conduction of thecompressed charges from the compression cylinder into the explosioncylinders, and two cams, one mounted on each side of the compressioncylfor operating each of said valves. f

` 9. ln a rotary internal combustion engine, the combination of a rotarycasing, said cas'- ing being divided up into three compartments, thecentral one constituting a compression chamber and the two end onesexplosion chambers, the interior'of said casing in each of the chambersbeing in the form of a heart-shaped cam, a piston in each of the three.chambers, the pistons being yieldingly mounted to. move radially againstthe surfaces of said cams, whereby the pistons will contact with saidsurfaces throu'hout each revolution', means for holding' the pistons inthe explosion chambers against rotation, means for rotating the pistonin the compression chamber in the opposite direction to that of thecasing and at the same` speed, the inward extension in the cam surfaceof the compression cylinder being located substantially in the sameposition as that of one ofthe explosion chambers'and in the oppositeposition to that of the other.

10. As' an article of manufacture, an expansion ring for a rotary enginehaving an outer circular surface and an inner spiral surface extendingfrom a thin end of the ring substantially throughout a circle to anyopposite thick end ot the ring and an inner cave surface ofthe ringhaving radial slots. Y

i 11. lin a krotary internal combustion engine, the combination of astationary shaft, a rotary cylinder having a cam-shaped surface inside,a piston mounted radially within said cylinder, yielding means forforcing said piston outwardly in a radial direction against said camsurface to l,form a tight joint, and means for rotating said piston atthe same speed as the cylinder but in the opposite direction and aboutthe sameaxis.

' 12. lin a rotary internal combustion engine, the combination with, astationary shaft, a rojarycasi'ng having a cam-shaped surface inside,and a piston mounted iradiallyv within said casing, 'of va pair of rodso'n which the pistonl isguided to reciprocate, a pair of springs on therods for holding the end oi the piston at .the extreme radial po.-

sition, a spider on the shaft on which said rods are located, saidspider having a spiral rovided with a of concentric circular form inwhich saiife sp sii expansion ring between the surfaces of the spiderand casing for preventing the e f the explosive mixture between em. 13.In a rotary internal combustion engine, the combination with a shaft, arotary casing having a cam-shaped surface inside and a piston mountedradially within said casing, of 'elding means for supporting said ypiston wit its end` against said cam surface a spider on said shaft forsupporting said piston, said spider having an outer surface of spiralformation and' the casing having an inner concentric circular surfacewithin which the spider is located, and an expan-v sion ring having anouter concentric circular surface fitting on the inside of the-casingand an inner spiralsurface fitting on the outside of the spider, andcapable of moving around the shaft to ensure a ti ht -joint. 14. In arotary vinternal com vstion Ven- 'gine, the combination with a shaft anda cylinder having a cam-shaped surface inside, said parts beingrelatively rotatable, A of a iston mounted radiall within said eylin er,inea'ns for yieldingy supporting said piston in a radial positionagainst said camsurface a spider on said shaft for supd for ltheexplosive mixture, the exterior of porting sai piston, saidJ spiderhaving an outer surface of spiral formation andV the cylinder having aninner concentric circular surface within which, the spider is located,

an expansion rin havin an outer concentric circular ace fitting on theinside of the piston, and an inner spiral surface Aiittin on the outsideof the s ider, and capabe of being moved circ erentially, and means of ayielding nature or pressing the ring :aroundA the circumference when thespace between the casing and spider coinmences to change. l

15. In a rotary internal combustion en- 5 e, the combination of a shaftand casing, /relativeiy rotatable separately a spider on said shaft, apiston mounted on said spider --and adapted to move radially, thercasinghaving a cam-shapedinterior against which 5 the end of said piston isadapted to Yengage to provide a chamber for the explosive mixture, theexterior of said spider and theinterior surface of said casing at itsends having a space -between them `gradually 55, widening around thecircumference, ,a tapered expansion ring fitting in and filling saidspace foipreventing the passage of the explosive mixture `between saidparts, 'a lever mounted on the spider and engaging the expansion rin anda sprin onl the ider for yieldipg y forcing said ever in a 'rection tomove the expansion around Jinadirectiontensureitslllingt espace betweenthe spider and casi 5h16. Inarotaryinternalco f 'onengine,

ider is located, and,

the combination of a relatively rotatable shaft and casing, a spider onsaid shaft, a piston mounted on said spider and adapted to moveradially, the casing having a camshaped interior against which the endof said piston presses to provide a chamber for the explosive mixture,the exterior of said spider v4aiid the interior surface of said casingat its ends having 'a space between them, an expansion ring fitting inand filling said s ace for 'preventing the=passage of t e ex p osivemixture between said parts, a lever mounted on'the spider and engagingthe expansion ring, a sprin on t e spider for yieldingly forcing sailever in a direction to move the expansion rin around for fillin thespace between the spi er and casing, sai expansion rin being circularand concentric with the shat on one side and of spiral formation on theother, the casin and spider being similarly shaped so that the expansionrin will fill the space in allI positions.'

1%. In a rotary internal combustion engine, the combination of arelatively rotatable shaft and casing, a s ider on said shaft, a pistonmounted on sai spider and adapt ed to` move on said spider and adaptedto inove. radially, the casing -having a camsha d interior against whichthe end of said)e piston presses to provide 'a chamber saidspider andthe interior surface of said casing at its ends having a space betweenthem gradually widening from one point to another, aii expansion ringfitting in and filling said space for preventing the assage of the exlosive mixture between sai parts, means or moving the expansion ringaround in a direction to increase its capacity for filling the spacebetween the spider and casing, said expansion ring bein thicker atponeend than at the other, andiaving a longitudinal space between its endsextending through its length, and means for closingsaid space.

18. Iii a rotaryinternal combustion engine, the combination of arelatively rotatable shaft and casing, a piston adapted to moveradially, the casing having a camshaped interior against which the endof sai piston presses to provide a chamber for the e losive mixture, any expansion ring fitting inside the casing for preventin the ypassage ofthe explosive mixture, sai expansion ring being thicker at one end thanat thether, and having a longitudinal space between its endsiextendingthroughout its length, means for closing said space comprising a pair ofplates located along the edges of the expansion ring and interlockingwith each other, and-leaving a spacebetween them for the piston saidplates being slidable circumferentially on each other, and two small endplates at the ends 0f the piston.

19.111 a rotary internal combustion engine, the combination of arelatively rotatable shaft and casing, a spider on said shaft, lapiston'mounted on said spider and 'adapt- -ed to move on said spider andadapted `t0 the explosive mixture between said parts,y

means' for moving the expansionl ring around in a direction to increaseits capaclty for filling the space between the splder and casing, saidexpansion ring bein .thicker aving a.;

at one end than at the other, and longitudinal space between its endsextending `through its length, means for closing said space, said meanscomprising a pair of plates located' along the edges of the expansionring longitudinally ofi-the shaft, and.

springs at their ends for normally ,holding there apart. o

20. ln agrotary internal' combustion engine the combination of'A a,stationary shaft, and one compression and two explosive cyl inders xedtogether and rotatable together aboutsaid shaft, of means for'conducting an explosive mixture into the compression y cylinder, apiston in eacli of the cylinders,

all of said cylinders having an interior cam formation 'for cooperatinwith the` respective pistons, ande means or conducting the compressedcharges alternately into the two explosion chambers, said sha-ft havingatv the end passages for oil and air." f 21Min a rotary internal.combustion engine, the combination of an exuansionfring and having .alongitudinal. space between for preventing` the passage of the explosivemixture, said expansion ring being thicker at one end vthan at theother, an having a longitudinal 'space between its ends extendingthroughout its length, a piston movable through said space, means forclosing` said s ace around the pistoncomprisng'a pair o platesloatedalong the edges of the expansion ring and interlocking with eachother, and leavinfr a space betweenv them for the piston, said pilatesbeing slidable circumferentially ongeach other, and two small en platesat the endsof the piston.`

22. In, a rotary'internal combustion'engine, the combination .with ashaft and a relatively rotatable cylinder,v the shaft have ing a hubhaving a spiral surface', of an ex`f pansion ring extending part -wayaround thecylinder for preventing the passage of the explosive mixture,means for moving the expansion ring, around in-the cylinder,saidexpansion ring being thicker" at one extreme end than at -the otherto fit on said surface,

its ends extending 4thi-ou' h its width, a. pain. of plates locatedalongt e edges of the expension ring longitudinally of the shaft,

and springs at their ends for normally clos ing the space betweentheends of the expansionfrlng.

23. As an article of manufacture, an expansion ring for a rotary en ehaving an outer concentric circular sur ace, and a sin-` gle internalspiral surfacez and ca able of being moved circumerentially, an means ofa yielding nature-for pressing the rin irzumferentially around the innersnit o y. v l -1 In testimony whereof I have hereunto affixed mysignature.

LAFAYETTE znnmn.

